Radio Communication System, Radio Communication Method, Radio Base Station and Control Station

1. A radio communication system comprising: a plurality of base stations, including a first base station and a second base station; wherein the first base station comprises: a first communication control unit configured to switch off a cell of the first base station, the cell having a respective Cell Global Identifier; the first communication control unit being configured to send, to the second base station, a first notification indicating that the cell corresponding to the respective Cell Global Identifier is switched off; and a second notification indicating deletion of information of the cell corresponding to the Cell Global Identifier; and wherein the second base station comprises a second communication control unit configured to maintain a neighbor relation configuration of the cell of the first base station even when the cell of the first base station is switched off, and to respond to the second notification sent from the first base station by deleting the information of the cell of the first base station corresponding to the Cell Global Identifier when the second notification is received.

2. The radio communication system according to claim 1 , wherein the second base station is further configured to respond to at least one of the first notification and the second notification by updating a neighbor cell list.

3. A base station, intended for use in a radio communication system, the base station comprising: a communication control unit configured to switch off a cell of the base station having a Cell Global Identifier and to send, to another base station, a first notification indicating switch off of the cell of the base station corresponding to the Cell Global Identifier, and a second notification requesting deletion of information of the cell of the base station corresponding to the Cell Global Identifier; and the communication control unit being configured to: maintain a neighbor relation configuration of another cell of the another base station even when the base station is informed that the another cell is switched off, and delete the information of the another cell in response to the second notification from the another base station.

4. A base station, intended for use in a radio communication system, the base station comprising: a communication control unit configured to receive a first notification indicating that a cell of another base station corresponding to a Cell Global Identifier is switched off and a second notification indicating deletion of information of the cell of the another base station corresponding to the Cell Global Identifier; the communication control unit being configured to: respond to the first notification by updating a neighbor cell list to reflect a switching off of the cell corresponding to the received Cell Global Identifier, and respond to the second notification by deleting information of the cell corresponding to the received Cell Global Identifier.

5. A communication method in a radio communication system including a plurality of base stations, the method comprising: switching off a cell of a first base station; sending to a second base station, a first a notification, including a Cell Global Identifier corresponding to the switched off cell, that the cell of the first base station corresponding to the Cell Global Identifier is switched off; and a second notification, including the Cell Global Identifier, requesting deletion of information of the cell of the first base station corresponding to the Cell Global Identifier; maintaining a neighbor relation configuration of the cell of the first base station even when the cell of the first base station is switched off, by the second base station; and responding to the second notification sent from the first base station by deleting the information of the cell of the first base station.

6. The method according to claim 5 , further comprising responding to the at least one of the first notification and the second notification by updating, by the second base station, a neighbor cell list.

7. A method of a base station in a radio communication system, comprising: receiving a first notification that a cell of another base station identified by a Cell Global Identifier is switched off and a second notification requesting that information of the cell of the another base station identified by the Cell Global Identifier is deleted; maintaining a neighbor relation configuration of the cell of the another base station even when the cell of the another base station is switched off; and deleting the information of the cell of the another base station when the second notification is received.

8. The method according to claim 7 , further comprising updating a neighbor cell list upon reception at least one of the first notification and the second notification from the first base station.

9. A method of a base station in a radio communication system, the method comprising: switching off a cell of the base station having a Cell Global Identifier; sending to another base station, a first notification indicating switch off of the cell of the base station corresponding to the Cell Global Identifier, and a second notification requesting deletion of information of the cell of the base station corresponding to the Cell Global Identifier; maintaining a neighbor relation configuration of another cell of the another base station even when the base station is informed that the another cell is switched off; and deleting the information of the another cell in response to the second notification from the another base station.

10. A method of a base station in a radio communication system, the method comprising: receiving a first notification indicating that a cell of another base station corresponding to a Cell Global Identifier is switched off and a second notification indicating deletion of information of the cell of the another base station corresponding to the Cell Global Identifier; responding to the first notification by updating a neighbor cell list to reflect a switching off of the cell corresponding to the received Cell Global Identifier; and responding to the second notification by deleting information of the cell corresponding to the received Cell Global Identifier.